A third teacher from a school already rocked by two sex scandals in the past two years admitted in court yesterday that he had exchanged explicit texts and photos with a 15-year-old pupil.

Terry Mann, 45, talked with the girl about converting his Land Rover into a "passion wagon" and used the nickname San Quentin after the notorious US jail, quipping that he would end up there if the relationship was exposed.

But he escaped joining two former colleagues in prison when a judge suspended a 12-month sentence after the IT teacher insisted that the pair were in love and committed to abstain from sex until the girl reached the age of consent. Mann, who is now divorced, was described at Hull crown court as a broken man, forced to give up teaching and earn a living by repairing computers part-time.

The court was told that he worked at the high school with the art teacher Ian Blott and the science teacher Steven Edwards, who are serving four- and five-year prison terms for having sex with underage pupils. Mann's case was the last to follow a major inquiry in East Yorkshire in which 11 teachers were investigated by police.

Helen Hendry, the prosecuting barrister, said that Mann had defied a headteacher's warning not to see the girl, and went on to film her kissing him in the back of his 4x4. He initially denied being attracted to her, but internet chat records showed them discussing sexual positions.

Mann told the police that his intentions were honourable and denied that he was anything like Blott and Edwards. Mann's barrister, Steven Garth, said: "He is an insecure and naive man. At the time he met this girl he was at a low ebb, with serious financial worries and suffering from depression.

"When this girl showed him some friendship he was flattered but unfortunately the friendship went too far. He has lost his job, his good name, his reputation and good character. He has lost his income of £33,000 a year and is likely to lose his home."

Blott, who is 55 and married, was jailed for four years in July 2006 for having sex with a 15-year-old on school trips to Paris and Edinburgh. Edwards, 35 and married, was jailed for five years last February for affairs with three girls who had sex with him in his car and in the school's science block.

Judge Roger Thorn QC told Mann, who admitted sexual activity with the girl and having two indecent photographs of her: "Children will, from time to time, admire, respect and occasionally fall in love with their teachers. Anybody in the caring profession surely knows the dangers it involves."

But the judge added that prison would not serve any purpose, so although there had to be a jail sentence, it would be suspended for three years. Mann was also ordered to attend a sex offenders' treatment programme, banned from working with children and ordered to sign the sex offences register for 10 years.